Figure 4a. Pancreaticoduodenal imaging in MEN 1: US. (a, b) Gastrinoma in a patient with hypergastrinemia. (a) Endoscopic US image shows a lesion (arrow) within the duodenal wall. (b) Endoscopic US image shows a focal hypoechoic lesion (arrow) in the pancreatic head. At surgery, the lesion proved to be a gastrinoma. (c) Insulinoma. Intraoperative US image obtained in a patient with a biochemically proved insulinoma but negative cross-sectional imaging findings demonstrates an adenoma (arrow) within the pancreatic body. (Case courtesy of Jane Phillips-Hughes, MD, John Radcliffe Hospital, Oxford, England.)